The high plateau of Mongolia, east of the Altai mountains, is rivalled only by Scandinavia as a region from which successive waves of tribesmen have emerged to prey upon more sedentary neighbours. Mongolia is the original homeland of both Turks and Mongols, two groups much intermingled in history and loosely related in their languages.

Mongolia is an ideal starting point for the movement of nomadic tribes in search of new pastures, and for sudden excursions of a more predatory nature. It lies at the extreme end of an unbroken range of open grasslands, the steppes, which reach all the way to Europe. Horsemen can move fast along the steppes. South of this nomadic highway live rich settled communities.

The emergence of the Turks from Mongolia is a gradual and uncharted process. Each successive wave makes its first appearance in history only when Turkish tribes or warriors acquire power in some new region, whether they be the Khazars, the Seljuks or one of many other such groups.

The sudden eruption of the Mongols from their homeland is different. Their astonishing expansion, spanning the breadth of Asia, can be precisely dated (to the early years of the 13th century) and can be attributed to the military genius of one man - born with the name of Temujin, but known now as Genghis Khan.

Gök Türk and the Khazars: 6th - 8th century

The first historical mention of the Turks is in Chinese accounts of a great empire established by a confederation of nomads in the 6th century AD. Stretching from north of the Great Wall in the east to the Black Sea in the west, the empire is known to the Chinese as T'u Küe and to the Turks themselves as Gök Türk, meaning Sky Turk.

This first expansion out of Mongolia is soon followed by a mysterious and powerful realm thought to be Turkish in origin - the empire of the Khazars, occupying the western part of the territory of Gök Türk. The Khazars surprise their contemporaries (and intrigue historians) by converting en masse to Judaism in the 8th century.

The Turks and Islam: 7th - 10th century

Turkish tribes to the east of the Khazars, settled around the cities of Bukhara and Samarkand, succumb to a powerful religious influence. Their own religion is shamanism but now they convert to Islam. This brings them within the Muslim caliphate, which from762 is based in Baghdad.

The Baghdad caliphate is in one sense the Persian empire in a new guise. Within this empire the Turks play an increasingly important role, both as tribal allies and as slaves in Persian armies. Gradually the Turks begin to carve out territories for themselves. The career of Subuktigin, in the 10th century, shows how it can be done.

Subuktigin of Ghazni: 10th century

Born near Lake Issyk-Kul in about 942, Subuktigin is captured as a boy by a rival Turkish tribe and is taken to the slave market in Bukhara. There he is sold to a Turkish officer serving in the Persian army. The Turkish officer is later put in command of the district around Ghazni, where he sets himself up as a semi-independent ruler.

Subuktigin, popular with the Turkish troops in the region, inherits the same position and extends his control over an increasingly large district - all in the name of his overlord, a Persian emperor of the Samanid dynasty. But by the time Subuktigin is succeeded by his son Mahmud, in 997, the military district of Ghazni has acquired almost the status of a kingdom.

Mahmud of Ghazni: 999-1030

Mahmud's rule coincides with the crumbling of the Samanid dynasty in Persia. From999, when the Samanid emperor loses his capital city (Bukhara), Mahmud treats Ghazni as his own kingdom. Over the next thirty years he greatly extends his territory, until it reaches to Isfahan in the west.

It also stretches eastwards into India, where Mahmud regularly campaigns from 1000 onwards. His incursions begin the process by which northern India falls to a succession of Muslim invaders. But his own empire in Afghanistan and eastern Iran succumbs soon after his death to a new wave of Turkish tribesmen pressing in from the north. The newcomers in this case are the Seljuks.

The rise of the Seljuks: 10th - 11th century

Seljuk is the chieftain of a group of Turkish tribes who migrate, in the late 10th century, from the steppes to the northern borders of the Persian empire - in the region around the Syr-Darya river. They embrace Islam, and are expected to play their part in the frontier defences of the Muslim world. But in the recurrent pattern of barbarians in the suburbs of civilization, they have their own ideas. They fancy a more central position.

The obvious stepping stone towards greater power is the newly formed Turkish realm, founded by Mahmud and centred on Ghazni. Mahmud, an experienced conqueror, dies in 1030. His son, Mas'ud, becomes the focus of Seljuk attention.

Mas'ud is campaigning in the eastern part of his empire, in India, when Togrul Beg, a grandson of Seljuk, strikes in the west. Mas'ud hurries home to confront this threat. He meets the Seljuk army in 1040 at Dandandqan, to the northeast of Mashhad, and is defeated.

The Seljuks establish their base in this border region between modern Iran and Afghanistan, while Togrul Beg looks further west for even greater prizes. Persia is in a state of anarchy, ruled by many petty princes (the majority of them Shi'as). The authority of the Sunni caliph in Baghdad is no more than nominal.

Togrul Beg gradually fights his way westwards through Persia. By 1055 he is in a position to enter Baghdad itself. He does so without violence, being welcomed by the caliph as a liberator from the Shi'as. The caliph gives him the title of sultan and an ambitious task - to overwhelm the Fatimids, the Shi'ite dynasty controlling the caliph's Egyptian territories.

This is beyond the powers of Togrul Beg and his still somewhat unruly Turkish tribesmen. But for the next two generations the Seljuk dynasty retains control in Baghdad and governs a Persian empire restored to extensive boundaries.

Byzantines and Turks: 1064-1071

In 1064 the Seljuk Turks, under their sultan Alp Arslan, invade Armenia - for many centuries a disputed frontier region between the Byzantine empire and neighbours to the east. Alp Arslan follows his success here with an attack on Georgia, in 1068. These acts of aggression prompt a response from the Byzantine emperor, Romanus IV Diogenes.

The armies meet in 1071 at Manzikert, near Lake Van. The battle, a resounding victory for the Seljuks, is a turning point in the story of the Byzantine empire. Within a few years there are Turkish tribes in many parts of Anatolia. Some of them are bitter enemies of the Seljuks, but the Seljuks are now the main power in this borderland between Islam and Christianity.

The Seljuks and the sultanate of Rum: 11th - 13th c.

Rum, meaning Rome, is the word used by the Turks for Byzantium (whose officials still describe themselves as Romans, in keeping with the origins of the Byzantine empire). Pressing deep into Anatolia, after the victory at Manzikert in 1071, the Seljuks reach Konya in the following year and Nicaea, much closer to Constantinople, in about 1080. They make Nicaea their capital until it is recovered by the Byzantines during the first crusade, in 1097. In 1099 Konya, strategically placed in the centre of Anatolia, becomes the Seljuk capital.

The Seljuks describe their new territory, at the heart of the old Byzantine empire, as the sultanate of Rum.

Throughout the 12th and 13th century Anatolia is in turmoil. Turkish tribes fight among themselves. The Byzantines try to recover their land. Crusaders, passing through and from 1204 occupying Constantinople, complicate the picture.

But the new and overriding feature is that Anatolia is now largely occupied by Turks. This fact enters the languages of the period. In addition to its many other names, the region begins to be referred to as Turkey - the land of the Turks. The new identity survives the arrival of the Mongols in the 13th century and the end of the Seljuk dynasty in the early 14th century. By then another Turkish tribe, the Ottomans, are making their mark.